Field of the Invention
Embodiments of the present invention generally relate to an article of footwear having an inflatable bladder; and more specifically to a pump unit including an external pump for inflating the inflatable bladder.
Background Art
Individuals are often concerned with the amount of cushioning an article of footwear provides, as well as the aesthetic appeal of the article of footwear. This is true for articles of footwear worn for non-performance activities, such as a leisurely stroll, and for performance activities, such as running, because throughout the course of an average day, the feet and legs of an individual are subjected to substantial impact forces. When an article of footwear contacts a surface, considerable forces may act on the article of footwear and, correspondingly, the wearer's foot. The sole functions, in part, to cushion to the wearer's foot and to protect it from these forces. To achieve adequate cushioning, many footwear soles are relatively thick and heavy. When sole size and/or weight are reduced to achieve other performance goals, protection of the wearer's foot is often compromised.
Although the human foot possesses natural cushioning and rebounding characteristics, the foot alone is incapable of effectively overcoming many of the forces encountered during every day activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue associated with every day activity is more acute, and its onset accelerated. The discomfort for the wearer that results may diminish the incentive for further activity. Equally important, inadequately cushioned footwear can lead to injuries such as blisters; muscle, tendon and ligament damage; and bone stress fractures. Improper footwear can also lead to other ailments, including back pain.
Proper footwear should complement the natural functionality of the foot, in part, by incorporating a sole (typically including an outsole, midsole and insole) and/or an upper which absorbs shocks and provides appropriate cushioning. Therefore, a continuing need exists for innovations in providing cushioning to articles of footwear. Furthermore, there is a need for innovations related to customized and/or tunable cushioning in articles of footwear.
Modern footwear and apparel include unique features that may be influential in why a consumer chooses to purchase a particular item. One way to capture the attention of potential consumers is to offer unique footwear with eye-catching features. Footwear and apparel having an inflatable bladder for providing support, cushioning and/or comfort is one example of a unique and attention-grabbing feature in modern footwear.
An inflatable bladder located within an article of footwear, apparel, or accessories can be inflated using an external (off-board) pump or an internal pump physically attached to the article of footwear. As such, a reliable and easy to use external pump for inflating a bladder located on an article of footwear is needed.